Improvement in steam-boilers



PATENT EErcE@ ROBERT I-IOOPER, OF BALTIMORE, MARYLAND.

IMPROVEMENT IN STEAM-BOILERS.

Specification forming part of Letters Patent No. 25,017, dated August 9, 1859.

To all whom it may concern,.-

Beit known that I, ROBERT HOOPER, of Baltimore, in the county of Baltimore and State of Maryland, have invented a new and useful Improvement in Steam-Boilers and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming a part of this specification, in which- Figure l is a vertical longitudinal section of the boiler. Fig. 2 is a top View, and Fig. 3 a front view, of the boiler.

Similar letters of reference in each of the several figures indicate corresponding parts.

The nature of my invention consists in contracting that part of the boiler immediately above the iire-ues, in combination with the widening and extending of that part which is beyond or in rear and above the end of the fire-box, substantially as hereinafter specified, whereby I obtain a greater depth of water, even whenthe quantity of water in the boiler is greatly lessened over the fire-iiues, than is obtained in ordinary forms of boilers, and at the same time accomplish such a small generation of steam that warning, through the slow running of the machinery being driven, will be given to the engineer that the water is getting low; but when the Water is at the proper level I obtain a larger amount of water-surface, and consequently accomplish a freer and more perfect generation of steam than is effected with boilers which have only the contracted throat without the extension water-surface which I employ for this purpose and for another object presently stated.

My invention consists, second, in forming a water-circulating passage below, in rear, and above the iire-box, and nearly or wholly isolating said passage from the fire-box by means of a large space existing between the fire-box and the partition-walls of the said water-circulatin g passage, substantially as hereinafter specified, whereby after the boiler is supplied with water and the generation of steam is going on the water passes upward from the hottest part or from near the heating-surfaces to the rear extension water-surface, where it loses some of its heat and rapidly descends by reason of its superior gravity and the draft or partial vacuum created at the iireor heating-surface by the rising of the more intensely-heated water through the downward isolated water-passage and along the lower isolated water-passage to the grate and mingles with the highly-heated Water surrounding the heating-surfaces, where it is again intensely heated and passes up through the contracted throat and again onto the enlarged water-surface, where the generation of steam occurs, and it again loses some of its heat and again commences to circulate as just described, and so on continuously.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation.

F is the furnace, having the usual tire-doors a. The back of the furnace is perforated for the reception of iire iiues or tubes b, which conduct the products of combustion into the chamber c, from which they are conducted by similar ilues CZ into the chamber E, and from thence by the smoke-pipe f into the open air. A water-space g entirely surrounds the furnace and iire-iiues. h is the upper part of the boiler connected by the Water-spaces fi and la with the water-space g, immediately surrounding the fire-chamber. l Z are watertubes connecting the upper part of the boiler with the water-space g. The boiler is contracted at m, immediately above the fire-dues, as shown in the drawings, or in any similar manner. The object of this contraction of the boiler is to obtain a greater height of water on the iire-lues than is obtained with the same quantity of water in any of the ordinary forms of boilers. Less steam will consequently be generated, greater security from explosion will be attained, and notification of low water, dangerous in other boilers, is safely indicated in my invention.

It is obvious that many modifications of my invention may be employed which will not differ in principle from it. For example, tubes might be employed to connect an upper with a lower water-s pace surronding the lire-fines in lieu of the contracted throat m, or a cylindrical boiler with a vertical hollow axis for the descending water and a' throat which takes a curved form instead of a parallel or straight form, or any other form of boiler which is in any manner contracted for the purpose described. I deem all these modifications as mere equivalents of my invention, and therefore do not wish to restrict myself to the particular form of boiler shown.

The operation of my invention is obvious. Fire being made in the furnace, the products of combustion pass out, as before described. The water in immediate contact With the fireues, being heated, rises to the top of the bo1ler,and the cooler portions descend through the spaces 7l and 7a to the space g, and thence circulate as before in a continuous current and arezrapidly converted into steam. By elongating the boiler or having it extend beyond the end of the lire-box and isolating said extended portion from the fire-box by a space z, as shown in the drawings, a rapid circulation is attained, which would not be the ease did the furnace or fire-chamber extend entirely under the boiler.

lVhat I claim as my invention, and desire to secure by Letters Patent, is-

l. Contracting that part of the boiler innlnediately above the fire-fines, in combination With the Widening and extending of that part Which is beyond or in rear and above the end of the lire-box, substantially as and for the purposes set forth.

2. Forming-a Water-circulating passage below, in rear, and above the fire-box, and nearly or Wholly isolating` said passage from the fireboX by means of a large space existing between the fire-box and the partition-Walls of the said Water-circulating passage, substantially as-and for the purposes set forth.

ROBERT HOOPER. Vitnesses:

ROBERT ATKINSON. THos. NV. JENKINS. 

